Old post, I know, but I found a workaround for this a few months back when I was under a time crunch. I did this on a 2010 MacPro with dual 2.4 GHz quad-core Intel Xeon processors, but I see no reason it couldn’t work with any multi cored machine.
Median is not a multithreaded filter, for whatever reason, AE will only use 100% of one of your threads to calculate it. You need to do a multi-machine render on your single machine to use all of your available cores/threads and speed up you render by a huge factor.
First you need to have BG renderer installed, it’s available from aescprits, it’s pretty much a crime that it’s not included with AE, it’s $35 bucks for the pro version, but it’s WELL worth it.
If you’re familiar with BG Renderer Pro and multi-machine rendering, I’ll cut to the chase: Render an image sequence, make sure you are set to “skip existing frames” in your render settings, and launch as many BG render instances as your computer can handle. (1-2 for each core).
If you’re not familiar with BG Renderer, buy it, download it, install it, then follow these steps:
1. Restart AE, launch BG renderer, and dock it in a window.
2. Set up your render, it will have to be an image sequence, you can’t do this with a single file output. If you need to finish in ProRes or something, you will have to compile the frame sequence into a single file afterwards, but re-rendering a pre-rendered image sequence into a single .avi or quicktime file will be a lot faster than waiting for median to do its thing.
3. Under Render Settings, make sure to check “skip existing frames” (or use the multi-machine Settings preset). Make sure you’re in 16-bit mode (i’m assuming here that you want to render in 16-bit or 32 or you wouldn’t be having the issue). You won’t get the usual pop-up warning from AE if you are still in 8-bit mode from BG Renderer. It will make a note in the terminal window, but it flies right past and you won’t notice it until your render is done.
4. Once you’re set to skip the existing frames, you can click the BG Render button, it will ask you to save the project, and then it will launch a terminal window and begin to render in the background. Wait until it’s started rendering frame 1 before you launch another. It will uncheck the item from your render queue automatically once it has launched the BG process. This is actually quite convenient as it allows you to simply recheck the box and hit the BG render button again. Wait until it launches and has begun to render the first unrendered frame. You’ll see your renders skipping the completed frames within the terminal. Repeat this until you have as many instances as your system can handle.
BG Renderer does not have a limit (that I have reached) for the number of renders you can have running at once. Of course if you have 2 cores, you may only want to launch 2-4. I have 8 cores and was able to launch 9 renders without grinding everything to a halt. RAM is also a factor here, the more you have, the better your machine can juggle these multiple renders. An intel hyper-threaded processor has two threads per core, but i wouldn’t recommend maxing your processor out completely unless you have a lot of RAM, I would guess you hit a point of diminishing returns at some point based on cores vs GB of RAM.
5. Wait until all of your BG renders say that they are finished, and your render is complete. You can do multiple shots at once this way as well, just set them all up at once, and after you hit the BG Render button, you’ll have to recheck all of the boxes.
Hope this helps, sorry it was a bit long winded, it’s a pretty simple process really.